Various vehicle side airbags equipped with features in consideration of protection of shoulders or upper arms have been known. An airbag for a side airbag device disclosed in Japanese Patent Application Publication No. 2001-114060 includes a base part provided on the back side to be positioned upstream of inflation gas during inflation and deployment and a main body part provided on the front side of the base part. The main body part includes a part that is recessed backward in a position corresponding to the vicinity of the shoulder of the occupant and lower and upper inflation parts that are branched to extend from the base part as a crossing position and positioned laterally to the chest and the head during inflation and deployment. A band-shaped tether that couples the vehicle inner side surface and the vehicle outer side surface is disposed inside the base part. The minimum opening area of the upper side flow passage on the upper edge side of the tether is set to be smaller than the minimum opening area of the lower side flow passage on the lower edge side of the tether.
A side airbag device disclosed in Japanese Patent Application Publication No. 2001-171468 includes a folded airbag stored in an inflatable and deployable manner at a side surface of the seat bag on the vehicle outer side. The airbag includes a base part to be positioned upstream of inflation gas during inflation and deployment and a main body part to be positioned in front of the base part during inflation and deployment. The main body part includes a lower inflation part to be positioned in front of the base part and an upper inflation part to be in communication with the upper part of the lower inflation part during inflation and deployment. The airbag has its upper inflation part folded into the lower inflation part in a flat spread out state and is internally rolled to the vehicle inner side along radial folding lines provided around the upper position of the base part so that the upper edge side comes closer to the base part side and stored in the folded state. According to the disclosure of Japanese Patent Application Publication No. 2001-171468, the airbag can be inflated and deployed with as little interference as possible with the arms of the occupant by displacement to the vehicle outer side even if the occupant's arms are positioned near the left and right edges of the seatback.
In a vehicle side airbag device disclosed in Japanese Patent Application Publication No. 2010-132072, an airbag is in a lower position than an armpit of an occupant on the vehicle front side of a shoulder restraining part and includes an arm support edge on which the upper arm of the occupant is to be placed. Therefore, when the upper arm of the occupant strikes the airbag after deployment of the airbag is completed, the upper arm of the occupant slides along the airbag to be placed on the arm support edge. Therefore, the amount of lapping between the upper arm and the chest of the occupant can be reduced as compared to conventional devices when viewed in the vehicle widthwise direction, so that the upper arm of the occupant can be restrained from coming between the chest of the occupant and the airbag.
A side airbag disclosed in Japanese Patent Application Publication No. 2013-147119, is a side airbag inflated and deployed to between an occupant and a door trim from a side of a seat and is formed to be inflated and deployed from the hip to the armpit of the occupant in the vehicle up-down direction, and the side airbag includes a surface inclined downward from the vehicle back side to the vehicle front side to have its upper part conform to the lower side of the upper arm of the occupant.
A side airbag device disclosed in Japanese Patent Application Publication No. 2013-216211, protects an occupant between the occupant and a side wall of the vehicle by an airbag adapted to protect the part of the body below the shoulders. The airbag has an inflation part formed by joining together opposed pieces of base fabric and a three-dimensionally shaped part. The opposed pieces of base fabric have a pair of notches formed in overlapping positions at a part of peripheral parts and joined in a stretched state in the thickness-wise direction of the inflation part. The three-dimensionally shaped part is positioned at the peripheral part of the inflation part and three-dimensionally formed in the thickness-wise direction of the inflation part by the joined pair of notches. In the disclosure of Japanese Patent Application Publication No. 2013-216211, an airbag is deployed on a side of the body, and the airbag in the process of deployment can be restrained from flipping up the upper arm of the occupant.
A side airbag device disclosed in Japanese Patent Application Publication No. 2014-88073 is a side airbag device including an airbag deployed in a space between a seated occupant and a door upon a vehicle side collision and an inflator that supplies the airbag with gas, and the airbag is separated at least into a first chamber supplied with gas directly from the inflator and deployed to a side of the shoulder of the occupant, a second chamber supplied with the gas supplied to the first chamber and deployed under the upper arm of the occupant, and a third chamber provided under the second chamber and supplied with the gas supplied to the second chamber and deployed.
A side airbag disclosed in Domestic Republication of PCT International Application No. WO 2011/087026, is a side airbag capable of restraining the arm from being pressed against the chest because of the inflation and sufficiently absorbing impact toward the chest, and the side airbag has an arm opposed part having a recessed shape and opposed to the arm of the occupant in a deployed state to push up the arm to such a position that the arm does not overlap the chest of the occupant.
In a vehicle side airbag device disclosed in Japanese Patent Application Publication No. 2013-154786, a main airbag part of the side airbag is inflated and deployed first on the vehicle back side of the upper arm of an occupant to come between the shoulder, chest, and hip of the occupant and a side door, and a sub bag part yet to be deployed is opposed to the back surface of the upper arm. The sub bag part is inflated and developed to push up the upper arm as the sewed part of the airbag tears by increase in the internal pressure after the main bag is completely inflated and deployed. At the time, force from the airbag can be prevented from being applied on the chest (ribs) through the upper arm bones, so that the internal pressure of the airbag can be set on the basis of the resistance of the ribs of the occupant.
Upon a collision against a side part of a vehicle such as a vehicle door, the vehicle side part may deform and have a dent and the like, so that a door trim, etc. may enter into the vehicle. At the time, a side airbag is inflated and deployed beside the occupant and carries out an occupant protecting function, while the arm of the occupant may be held between the chest and the inflated side airbag as described in some abovementioned documents, so that the arm of the occupant may be pressed against the chest and the chest may get injured. In order to avoid the situation, various side airbags configured to flip up the occupant's arm have been proposed.
However, it is undesirable for the arm to be flipped up in response to the completion of inflation and deployment of a side airbag in a collision level which does not exactly require the movement. Stated differently, the arm would preferably be protected by the side airbag instead of being flipped up in some cases.
On the other hand, it is important to protect the shoulders of the occupant, and there has been a demand for a new idea for a side airbag capable of protecting the chest by flipping up the arm as required and protecting the shoulder at the same time.
The present invention is in view of the problem associated with the conventional features, and it is an object of the invention to provide a vehicle side airbag device including a shoulder protection part and a chest protection part and capable of protecting the chest by the chest protection part that lifts the arm softly rather than flipping as required depending on a collision state while protecting the shoulder by the shoulder protection part.